1. Field of the Invention
This invention relates to an illumination device for a vehicle compartment. More particularly, this invention relates to an illumination device for illuminating the interior of a vehicle compartment, for example, when an occupant gets on and off the vehicle. The illumination device according to the invention can be utilized as, for instance, a room lamp, which is installed on a roof portion in a vehicle compartment, and a door courtesy-lamp installed on each-of vehicle doors.
2. Related Art
An illumination device (that is, a room lamp) for illuminating a vehicle compartment in the night is installed on the roof portion in the interior of an automobile. Such a room lamp incorporates a light source adapted to perform turning on and off operations by linking such operations with opening and shutting motions of a door. When the automobile is in a state in which one of the doors thereof is opened (that is, when an occupant gets on or off the automobile), the room lamp illuminates the interior thereof to thereby assist the occupant to safely get on or off the automobile.
Meanwhile, it is desired to provide a room lamp enabled to have a high degree of a presentation effect or decoration effect of light in addition to the illuminating function. Conventional room lamps adapted to perform a presentation (that is, a fade-in), in which it becomes gradually lighter in a vehicle compartment, for example, when a door is opened, and a presentation (that is, a fade-out), in which conversely, it becomes gradually darker therein when the door is opened, have been put into practical use as a means for meeting such a demand. Although such a room lamp can obtain the decoration effects to some extent owing to illumination change, the representation effects are low. Further, the illuminating manner thereof lacks-in a feeling of luxury.
On the other hand, a conventional method enabled to enhance presentation effects by linking the turning-on of the room lamp with that of another illumination device, such as a door courtesy lamp, has been proposed (see Japanese Utility Model Publication No. JP-U-5-46576). However, such a conventional method simply causes a change of a place, to which light is radiated, according to the state of a door. Thus, this conventional method cannot obtain decoration effects so much.
Additionally, there has been proposed a conventional room lamp system adapted to change the color of illuminating light according to the state of a vehicle, which is changed between a door-opened state and a door-closed state, by using a white light lamp and a color light lamp as light sources and by controlling the illuminating condition of these lamps (see Japanese Patent Publication No JP-A-10-166940). Such a conventional room lamp system illuminates the interior of the vehicle with different colors of the illuminating light according to the state of the door. Thus, this conventional room lamp system achieves decoration effects. However, while this conventional room lamp system achieves unexpected presentation effects owing to an instantaneous changeover from white light illumination to color light illumination, performed in the door-opened state and in the door-closed state respectively, such the presentation effect is far from a desirable one in terms of feeling of luxury.